Third-harmonic generation imaging of laser-induced breakdown in glass

Summary form only given. Laser-induced breakdown in transparent materials has been studied extensively and has received growing attention with the development of high power femtosecond laser systems. Recent studies have shown that is possible to use these effects for three-dimensional optical data storage in transparent materials. In these studies the data were "written" with 0.5 /spl mu/J, 100 fs optical pulses at 760 nm from an amplified Ti:sapphire laser focused to a spot of approximately 1 /spl mu/m/sup 2/. The created pattern was subsequently "read" using transmission microscopy. In the paper we demonstrate, for the first time to our knowledge, the use of third-harmonic generation (THG) imaging to detect optically induced changes in the media, and read the optically imprinted pattern. The advantage of this approach is that the same laser beam can be used as a "write" and "read" beam, providing an excellent spatial (micron resolution), and temporal (femtosecond resolution) diagnostic for the induced change in microstructure.